1. Field of the Invention
This invention relates to variable dampers that regulate air flow through passageways, such as grates. The dampers are positioned in or adjacent the passageways and have one or more members that selectively and variably block air passing through the passageways.
2. Background of the Invention
There are certain environments in which it may be desirable to regulate the air flow through a passageway such that different volumes of air are permitted to pass through different zones of the passageway. One such environment is a data center, and the subject passageway is an access floor grate panel in the data center, as discussed below.
A typical data center includes multiple IT racks. The equipment supported by those racks, and the associated cables and other accessories, generate a relatively high amount of heat. Because of that heat, providing adequate cooling to IT racks in the data center is of paramount importance. Moreover, it is desirable that the IT racks be cooled as efficiently as possible, as the energy costs to cool IT racks may approach a large percentage of the energy costs to operate the data center.
Data centers typically have a raised floor system, often called an access floor system. An access floor system is usually comprised of a continuous array of floor panels, arranged edge-to-edge, and supported above the sub-floor by support structure. The array of access floor panels usually extends wall-to-wall in the data centers.
A plenum is formed between the sub-floor and the access floor panel array. Cables, wires, hoses, etc. are located in the plenum, and the plenum is also used as a conduit for cooling air. Often, one or more air conditioning units supply air to the plenum, and some of the access floor panels in the access floor panel array have grates. The cooling air passes through the grates into the data center.
The access floor panels with grates are usually positioned immediately adjacent to IT racks, and may have vanes that direct the cooling air that passes through the grates toward the IT racks.
A typical IT rack supports a variety of electronic equipment. The equipment is often unevenly distributed throughout the rack, including vertically. In that regard, an IT rack may have shelves, spaced vertically. Different equipment may be placed on the different individual shelves.
Different IT equipment generates different amounts of heat. Thus, the heat generated by the equipment at one vertical height of an IT rack (e.g., on one shelf) may differ from the heat generated by the equipment at another vertical height of the same IT rack (e.g., on a different shelf). However, the prior art IT rack cooling apparatus does not take into account that difference in heat at the various heights. Rather, usually there are temperature sensors at various locations of an IT rack, and the volume of cooling air is determined for the whole rack based on the readings of those sensors. In fact, often the volume of cooling air for the entire rack is based on the highest sensed temperature in the IT rack. That is, the entire IT rack is subjected to the volume of cooling air necessary to cool the hottest area or zone in the rack, even the areas or zones of the rack that are already much cooler than the hottest area or zone.
This results in inefficient cooling of the IT racks, because the cooling air is directed at the same volume to all areas of the IT rack based on the highest temperature in the rack, even to those areas that may need little, if any, cooling. More efficient and economical cooling would be achieved if larger amounts of cooling air are directed to the hottest areas of the IT racks, while lesser amounts of cooling air are directed to the other, cooler areas of the IT rack. Thus, in a data center, there is a need for cooling apparatus that directs different amounts of cooling air to different areas of or zones in the IT racks in the data center.